1. Field of the Invention
The present invention relates to information processing apparatuses and methods, information processing systems, and program storage media. More specifically, the present invention relates to an information processing apparatus and method, an information processing system, and a program storage medium which allow a predetermined information processing apparatus to acquire an access right to another predetermined information processing apparatus on a network implemented by an IEEE (Institute of Electrical and Electronic Engineers) 1394 high-speed serial bus.
2. Description of the Related Art
Networks based on SBP-2 (Serial Bus Protocol 2) are being more commonly used. SBP-2 is a communications protocol which is believed to be optimal for a connection implemented by an IEEE 1394 high-speed serial bus standard (hereinafter also referred to simply as IEEE 1394).
FIG. 1 shows a network implemented by connecting personal computers and an HDD compatible with the conventional SBP-2 based on IEEE 1394. A personal computer 1a is connected to an HDD (Hard Disk Drive) 2 via an IEEE 1394 connection unit 3. Although the HDD 2 is shown separately in the figure in order to show the connection with the personal computer 1a, the HDD 2 is actually incorporated in and mounted on the personal computer 1a. The personal computer 1a and a personal computer 1b (hereinafter simply referred to as a personal computer 1 unless a distinction therebetween is necessary, and the same applies to other apparatuses) are connected to each other via an IEEE 1394 cable 4.
According to the SBP-2 standard, for example, on the network implemented as shown in FIG. 1, a device which initiates an action (transmits an operation command), such as the personal computer 1, is referred to as an “initiator”, and a device which operates based on the command from the initiator, such as the HDD 2, is referred to as a “target”.
In the network implemented as shown in FIG. 1, a target is allowed to accept an access from only one initiator (i.e., a target cannot be shared by a plurality of initiators). That is, of the personal computers 1a and 1b, a personal computer 1 which has accessed the HDD 2 earlier occupies the access right to the HDD 2 (a race condition), thereby determining the access right.
Based on the Race condition, for example, in the network shown in FIG. 1, if the personal computer 1b accesses the HDD 2 first, the personal computer 1a, even though it incorporates the HDD 2, is not allowed to access the HDD 2 incorporated therein, the access right being occupied by the personal computer 1b connected via the network.
In order to overcome this problem, it has been proposed that the access right be set in the order of connections based on IEEE 1394. However, the setting changes when the order of connection is changed, failing to provide a fundamental solution to the problem.
Furthermore, in order to solve the problem, it has also been proposed that the access right be set only to initiators which request an access right with a correct password using the password function provided in the SBP-2 standard. However, if the password is known to a plurality of initiators, similarly to the above, of the initiators to which the password is known, the initiator which has accessed first occupies the access right to a target, failing to provide a fundamental solution to the problem.